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Wyoming-Montana Water Science Center
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ABOUT THE WYOMING-MONTANA WATER SCIENCE CENTER
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USGS Water Science Centers are located in each state.
Wyoming Groundwater-Quality Monitoring Network
A wide range of activities have the potential to contaminate groundwater. In addition, several naturally occurring constituents can limit the suitability of groundwater for some uses. The State of Wyoming has established rules and programs to protect groundwater quality, as well as agencies to implement the rules and programs. The Wyoming Groundwater-Quality Monitoring Network (WGQMN) is one such program the Wyoming Department of Environmental Quality (WDEQ) is implementing to evaluate the State's groundwater.
The WGQMN samples wells to establish baseline groundwater quality in priority areas where groundwater has been identified as an important source of public or private water supplies, is susceptible to contamination, and is overlain by one or multiple land-use activities that could negatively impact groundwater resources (Bedessem and others, 2005, fig. 1). The WGQMN project area consists of 33 priority areas (table 1) identified by the Wyoming Department of Environmental Quality's Aquifer Prioritization for Ambient Ground Water Monitoring project in the 7 principal river basins of the state. Although the scope of this project is statewide, initial efforts have been limited to specific river basins. Priority areas were grouped together to be sampled based on principal river basins.
Objectives of the WGQMN are to:
Groundwater samples are collected from existing shallow wells. Wells are stratified by depth (less than 500 feet), and aquifer type (alluvial or shallow bedrock). Upon further evaluation of data, a subset of wells are selected to include in the WGQMN. All samples are analyzed for standard analytes including major ions, trace elements, nutrients, dissolved organic carbon, total dissolved solids, alkalinity, volatile organic compounds, gasoline range organics, diesel range organics, dissolved hydrocarbon gases (methane, ethene, ethane), table 2).and total coliform and Escherichia coli bacteria. Additionally, selected samples are analyzed for supplemental analytes waste water compounds, tritium, gross alpha and gross beta radioactivity, and radon-222 (
Before sampling a well, the depth to water is measured, if possible. Wells are pumped (purged) until it is apparent that aquifer water, rather than water stored in the casing, is being sampled. If no pump is installed, a submersible pump is used for purging and sampling. Water temperature, pH, specific conductance, dissolved oxygen, oxidation-reduction potential, and turbidity are measured and recorded periodically during purging.
Samples are collected in accordance with specific USGS sampling protocols (USGS, 1997-present) to ensure a quality sample. Samples are containerized and preserved according to the analysis method's requirements, and shipped to either the EPA Region 8 Laboratory or a USGS analytical laboratory, depending on the analysis to be performed.
In addition to collecting samples, details about the well being sampled are useful for analyzing data. These data include photographs, geographic coordinates, water levels, and information about sampling conditions and well construction. All data are stored at the USGS office in Cheyenne, and much of the data are available on the internet at http://wy-mt.water.usgs.gov/projects/gw_monitoring/groundwater.htm.
Sampling by the USGS, in cooperation with the WDEQ, began in the Greater Green River Basin in December 2009 - including 4 additional wells sampled as part of the Wyoming Landscape Conservation Initiative. Sampling efforts moved to the Platte River Basin in November 2010 because of concerns about potential groundwater contamination from increased oil and gas development in the Niobrara shale formation. To date, sampling has been conducted in Albany, Campbell, Carbon, Converse, Crook, Goshen, Johnson, Laramie, Niobrara, Platte, Sheridan, Sublette, Sweetwater, and Uinta counties.
A fact sheet describing the WGQMN design and objectives, field procedures, and water-quality analyses was published in April 2011 and is available online at: http://pubs.usgs.gov/fs/2011/3041/. A scientific-investigations report describing the water-quality data through water year 2013 was published in 2014 and is available online at: http://pubs.usgs.gov/sir/2014/5130/.
Bedessem, M.E., Casey, D., Frederick, K., and Nibbelink, N., 2005, Aquifer Prioritization for Ambient Ground Water Monitoring: Ground Water Monitoring and Remediation 25, no. 1, pp 150-158.
Boughton, G.K., 2011, Wyoming Groundwater-Quality Monitoring Network: U.S. Geological Survey Fact Sheet 2011–3041, 4 p.
Boughton, G.K., 2014, Groundwater-Quality Characteristics for the Wyoming Groundwater-Quality Monitoring Network, November 2009 through September 2012: U.S. Geological Survey Scientific Investigations Report 2014–5130, 80 p., appendix.
U.S. Geological Survey, 1997-present, National field manual for the collection of water-quality data: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, chaps. A1-A9, 2 v., variable pagination. Chapters originally were published during 1997-1999; updates and revisions are ongoing and are summarized at http://water.usgs.gov/owq/FieldManual/mastererrata.html
For more information, contact:
Gregory K. Boughton
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